Now, if this door makes the classic PphssshshmStar Trek door noise when it opens and shuts, the manufacturers are onto a winner. It sounds like a neat solution for dogs and cats that like to roam: you pop a weatherproof RFID tag in their collar, and when they approach the Plexidor pet door it automatically slides up to let your pets in or out. Its safety mechanism means it won't guillotine your pet if they dawdle, and it shuts automatically so you only get your animals in your home. It's made of the same stuff as football helmets, so it should withstand some tough weather, and it's available now for between $130 and $800, depending on features and size. [Electronic House]